• Journal of Microbiology
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• 제38권4호
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• pp.270-274
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• 2000

Pathogenic Salmonella typhimurium can invade the intestinal epithelium and cause a wide range of diseases including gastroenteritis and bacteremia in human and animals. To identify the genes involved in the infection, the invasion determinant was obtained from S. typhimurium 82/6915 and was subcloned into pGEM-7Z. A subclone DHl (pSV6235) invaded HEp-2 and Chinese hamster ovary epithelial cells and contained a 4.4 kb fragment of S. typhimurium genomic region. Compared with the host strain E. coli DHl, the subclone DHl (pSV6235) invaded cultured HEp-2 and Chinese hamster ovary cells at least 75- and 68-fold higher, respectively. The invasion rate of E. coli DHl for the cells significantly increased by harbouring the genomic region derived from pathogenic S. typhimurium 82/6915.

• 한국식품영양과학회지
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• 제21권4호
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• pp.454-459
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• 1992

수종의 Aspergillus속 및 Penicillium속 균이 생산하는 진균대사 산물인 kojic acid가 독성분해 활성제의 첨가유무에 관계없이 Chinese hamster 난소세포에 염색체 변이를 일으키는 것이 확인되었다. Kojic acid 처리량의 증가에 따라 염색체 변이 또한 증가되었다. Kojlc acid의 잠재독성에 관한 본 실험결과에 기초해 이는 일종의 변이 유기체로 추정되며 현재로는 식품첨가제로서의 사용에 문제가 있는 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.1036-1040
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• 2007

Sodium butyrate (NaBu) has been used to enhance protein expression levels in mammalian cell culture. To determine the clonal variability of recombinant Chinese hamster ovary (rCHO) cells in response to NaBu addition regarding specific antibody productivity $(q_{Ab})$, three rCHO clones were subjected to different concentrations of NaBu. For all three clones, NaBu addition inhibited cell growth and decreased cell viability in a dose-dependent manner. On the other hand, the enhancing effect of NaBu on $q_{Ab}$ varied significantly among the clones. NaBu addition enhanced the antibody production of only one clone. RT-PCR analysis revealed that the changes in $q_{Ab}$ correlated linearly with those of the mRNA transcription level. Thus, it was concluded that the different enhancing effects of NaBu on protein expression in rCHO cell clones resulted from their different mRNA transcription levels.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.231.2-231.2
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• 2003

The efficient EPO (Erythropoietin) expression system in Chinese Hamster Ovary (CHO) cells was devised through the removal of ammonium ion accumulated in the media by introducing urea cycle enzymes. Previously, we developed C05 cell by transfecting the carbamoly phosphate synthase (CPS) and ornithine transcarbamoylase (OTC) into the EPO expressing CHO cell, IBE. (omitted)

• 미생물학회지
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• 제38권4호
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• pp.270-270
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• 2002

Pathogenic Salmonella typhimurium can invade the intestinal epithelium and cause a wide range of diseases including gastroenteritis and bacteremia in human and animals. To identify the genes involved in the infection, the invasion determinant was obtained from S. typhimurium 82/6915 and was subcloned into pGEM-7Z. A subclone DHl (pSV6235) invaded HEp-2 and Chinese hamster ovary epithelial cells and contained a 4.4 kb fragment of S. typhimurium genomic region. Compared with the host strain E. coli DHl, the subclone DHl (pSV6235) invaded cultured HEp-2 and Chinese hamster ovary cells at least 75- and 68-fold higher, respectively. The invasion rate of E. coli DHl for the cells significantly increased by harbouring the genomic region derived from pathogenic S. typhimurium 82/6915.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1397-1401
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• 2005

Bone morphogenetic protein-4 (BMP-4) is a signaling homodimeric molecule that acts as a morphogen to influence cell fate in a concentration-dependent manner. The limited supply of a pure preparation of BMP-4, due to very low level of their expression in vivo, makes it difficult not only to study the biological activities of BMPs, but also to use them as a clinical tool. For a large-scale production of BMP-4, human BMP-4 cDNA was expressed in Chinese hamster ovary (CHO) cells by a recently development vector system, which confers position-independent stable expression of the foreign genes. The CHO cell line expressing recombinant human BMP-4 (rhBMP-4) at the level of $7\;{\mu}g/ml$ could be obtained after stepwise selection with methotrexate. This level of expression is about 70 times higher than those previously reported. The partially processed form of BMP-4 as well as mature form could be detected, when the aliquots of culture media were analyzed by Western blot. The glycosylation pattern and biological activity of the rhBMP-4 were determined by glycosidase treatment and the induction rate of alkaline phosphatase in mouse osteoblastic cells.

• Journal of Preventive Medicine and Public Health
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• 제23권2호
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• pp.178-184
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• 1990

In order to examine the mutagenicity of cadmium dichloride the author studied the induction of sister chromatid exchanges in chinese hamster ovary $K_1$ cells which treated with cadmium dichloride at various concentrations. The results obtained were as follows : 1. In cells treated with $10^{-4}M$ cadmium dichloride, a small number of cells were viable but no mitosis was bound. 2. The frequencies of sister chromatid exchanges in cells treated with $10^{-5}M\;and\;10^{-6}M$ cadmium dichloride as $10.7{\pm}1.9\;and\;8.3{\pm}2.1$, respectively, were significantly increased for control ($6.0{\pm}2.3$). (P<0.05). 3. There were dose-dependent relationship between the concentration of cadmium dichloride and frequency of sister chromatid exchanges in cells treated with cadmium dichloride at concentration ranging from $10^{-5}\;to\;10^{-7}M$.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.100-100
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• 2002

As an preliminary experiment for making transgenic animals producing human follicle stimulating hormone (hFSH), we tried to express recombinant hFSH gene in vitro. hFSH is a heterodimeric glycoprotein hormone produced in the anterior pituitary gland. The hormone is essential in the regulation of reproductive processes, such as follicular development and ovulation. Genes encoding the common gonadotrophin alpha subunit and FSH-specific beta subunit were inserted into retroviral vectors under the control of the rat beta actin promoter. Gene transfer to the Chinese hamster ovary (CHO) cells was done by infection of the retroviruses harvested from PT67 packaging cells transfected with recombinant retrovirus vector DNA. After selection with G4l8, PCR and RT-PCR analyses of the G4l8-resistant CHO cells showed successful transfer and expression of both ${\alpha}$ and ${\beta}$ fragments of the FSH gene.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.810-815
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• 2004

Many biological properties and the clinical potential of human interleukin-2 (hIL-2) draw much attention to its high-level expression in mammalian cells. Recombinant human IL-2 (rhIL-2) was expressed in Chinese hamster ovary (CHO) cells, using the recently developed expression system which confers position-independent expression. Stable CHO cell lines carrying several hundred amplified copies of the rhIL-2 gene were easily obtained and rhIL-2 was expressed at high levels after selection with increasing concentrations of methotrexate. Interestingly, the insertion of the transcription terminator of the human gastrin gene into the downstream region of the gene for rhIL-2 considerably increased rhIL-2 expression. Using the expression system with the transcription terminator, it was possible to get a CHO cell line expressing the rhIL-2 at a very high level, about $11.4\mug/10^6$ cell/day, which is about 6 times higher than that previously reported. The biological activity of the rhIL-2 protein purified from the cell line was also confirmed by the cell proliferation assay.

• KSBB Journal
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• 제28권2호
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• pp.86-91
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• 2013

To date, various strategies have been studied to increase specific productivity in Chinese hamster ovary (CHO) cell cultures. Also, albumin-fusion platform is being applied to other important bioactive peptides with short half-lives. Here, we investigated the effects of silkworm gland hydrolysate (SGH) on the production of albumin-erythropoietin (Alb-EPO) in transgenic CHO cells. The viable cell density of CHO cells was increased by 13% in the medium containing 1 mg/mL SGH higher than in the control medium without SGH. In addition, the production of Alb-EPO was also 1.26- fold enhanced by reducing the early apoptosis of CHO cells. In conclusion, SGH could be used as a useful supplement for the enhancement of recombinant protein production.